--- /dev/null
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <signal.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+/*
+ * Code for dealing with input/output redirection.
+ */
+
+#include "shell.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "expand.h"
+#include "redir.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "options.h"
+
+
+#define EMPTY -2 /* marks an unused slot in redirtab */
+#define CLOSED -1 /* fd was not open before redir */
+
+
+struct redirtab {
+ struct redirtab *next;
+ int renamed[10];
+ int fd0_redirected;
+};
+
+
+static struct redirtab *redirlist;
+
+/*
+ * We keep track of whether or not fd0 has been redirected. This is for
+ * background commands, where we want to redirect fd0 to /dev/null only
+ * if it hasn't already been redirected.
+*/
+static int fd0_redirected = 0;
+
+static void openredirect(union node *, char[10 ]);
+static int openhere(union node *);
+
+
+/*
+ * Process a list of redirection commands. If the REDIR_PUSH flag is set,
+ * old file descriptors are stashed away so that the redirection can be
+ * undone by calling popredir. If the REDIR_BACKQ flag is set, then the
+ * standard output, and the standard error if it becomes a duplicate of
+ * stdout, is saved in memory.
+*
+ * We suppress interrupts so that we won't leave open file
+ * descriptors around. Because the signal handler remains
+ * installed and we do not use system call restart, interrupts
+ * will still abort blocking opens such as fifos (they will fail
+ * with EINTR). There is, however, a race condition if an interrupt
+ * arrives after INTOFF and before open blocks.
+ */
+
+void
+redirect(union node *redir, int flags)
+{
+ union node *n;
+ struct redirtab *sv = NULL;
+ int i;
+ int fd;
+ char memory[10]; /* file descriptors to write to memory */
+
+ INTOFF;
+ for (i = 10 ; --i >= 0 ; )
+ memory[i] = 0;
+ memory[1] = flags & REDIR_BACKQ;
+ if (flags & REDIR_PUSH) {
+ sv = ckmalloc(sizeof (struct redirtab));
+ for (i = 0 ; i < 10 ; i++)
+ sv->renamed[i] = EMPTY;
+ sv->fd0_redirected = fd0_redirected;
+ sv->next = redirlist;
+ redirlist = sv;
+ }
+ for (n = redir ; n ; n = n->nfile.next) {
+ fd = n->nfile.fd;
+ if (fd == 0)
+ fd0_redirected = 1;
+ if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
+ n->ndup.dupfd == fd)
+ continue; /* redirect from/to same file descriptor */
+
+ if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
+ INTOFF;
+ if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) {
+ switch (errno) {
+ case EBADF:
+ i = CLOSED;
+ break;
+ default:
+ INTON;
+ error("%d: %s", fd, strerror(errno));
+ break;
+ }
+ }
+ sv->renamed[fd] = i;
+ INTON;
+ }
+ openredirect(n, memory);
+ INTON;
+ INTOFF;
+ }
+ if (memory[1])
+ out1 = &memout;
+ if (memory[2])
+ out2 = &memout;
+ INTON;
+}
+
+
+static void
+openredirect(union node *redir, char memory[10])
+{
+ struct stat sb;
+ int fd = redir->nfile.fd;
+ const char *fname;
+ int f;
+ int e;
+
+ memory[fd] = 0;
+ switch (redir->nfile.type) {
+ case NFROM:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, O_RDONLY)) < 0)
+ error("cannot open %s: %s", fname, strerror(errno));
+ break;
+ case NFROMTO:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
+ error("cannot create %s: %s", fname, strerror(errno));
+ break;
+ case NTO:
+ if (Cflag) {
+ fname = redir->nfile.expfname;
+ if (stat(fname, &sb) == -1) {
+ if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0)
+ error("cannot create %s: %s", fname, strerror(errno));
+ } else if (!S_ISREG(sb.st_mode)) {
+ if ((f = open(fname, O_WRONLY, 0666)) < 0)
+ error("cannot create %s: %s", fname, strerror(errno));
+ if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
+ close(f);
+ error("cannot create %s: %s", fname,
+ strerror(EEXIST));
+ }
+ } else
+ error("cannot create %s: %s", fname,
+ strerror(EEXIST));
+ break;
+ }
+ /* FALLTHROUGH */
+ case NCLOBBER:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
+ error("cannot create %s: %s", fname, strerror(errno));
+ break;
+ case NAPPEND:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+ error("cannot create %s: %s", fname, strerror(errno));
+ break;
+ case NTOFD:
+ case NFROMFD:
+ if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
+ if (memory[redir->ndup.dupfd])
+ memory[fd] = 1;
+ else {
+ if (dup2(redir->ndup.dupfd, fd) < 0)
+ error("%d: %s", redir->ndup.dupfd,
+ strerror(errno));
+ }
+ } else {
+ close(fd);
+ }
+ return;
+ case NHERE:
+ case NXHERE:
+ f = openhere(redir);
+ break;
+ default:
+ abort();
+ }
+ if (f != fd) {
+ if (dup2(f, fd) == -1) {
+ e = errno;
+ close(f);
+ error("%d: %s", fd, strerror(e));
+ }
+ close(f);
+ }
+}
+
+
+/*
+ * Handle here documents. Normally we fork off a process to write the
+ * data to a pipe. If the document is short, we can stuff the data in
+ * the pipe without forking.
+ */
+
+static int
+openhere(union node *redir)
+{
+ const char *p;
+ int pip[2];
+ size_t len = 0;
+ int flags;
+ ssize_t written = 0;
+
+ if (pipe(pip) < 0)
+ error("Pipe call failed: %s", strerror(errno));
+
+ if (redir->type == NXHERE)
+ p = redir->nhere.expdoc;
+ else
+ p = redir->nhere.doc->narg.text;
+ len = strlen(p);
+ if (len == 0)
+ goto out;
+ flags = fcntl(pip[1], F_GETFL, 0);
+ if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) {
+ written = write(pip[1], p, len);
+ if (written < 0)
+ written = 0;
+ if ((size_t)written == len)
+ goto out;
+ fcntl(pip[1], F_SETFL, flags);
+ }
+
+ if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
+ close(pip[0]);
+ signal(SIGINT, SIG_IGN);
+ signal(SIGQUIT, SIG_IGN);
+ signal(SIGHUP, SIG_IGN);
+ signal(SIGTSTP, SIG_IGN);
+ signal(SIGPIPE, SIG_DFL);
+ xwrite(pip[1], p + written, len - written);
+ _exit(0);
+ }
+out:
+ close(pip[1]);
+ return pip[0];
+}
+
+
+
+/*
+ * Undo the effects of the last redirection.
+ */
+
+void
+popredir(void)
+{
+ struct redirtab *rp = redirlist;
+ int i;
+
+ for (i = 0 ; i < 10 ; i++) {
+ if (rp->renamed[i] != EMPTY) {
+ if (rp->renamed[i] >= 0) {
+ dup2(rp->renamed[i], i);
+ close(rp->renamed[i]);
+ } else {
+ close(i);
+ }
+ }
+ }
+ INTOFF;
+ fd0_redirected = rp->fd0_redirected;
+ redirlist = rp->next;
+ ckfree(rp);
+ INTON;
+}
+
+/* Return true if fd 0 has already been redirected at least once. */
+int
+fd0_redirected_p(void)
+{
+ return fd0_redirected != 0;
+}
+
+/*
+ * Discard all saved file descriptors.
+ */
+
+void
+clearredir(void)
+{
+ struct redirtab *rp;
+ int i;
+
+ for (rp = redirlist ; rp ; rp = rp->next) {
+ for (i = 0 ; i < 10 ; i++) {
+ if (rp->renamed[i] >= 0) {
+ close(rp->renamed[i]);
+ }
+ rp->renamed[i] = EMPTY;
+ }
+ }
+}
projects / apple / shell_cmds.git / blobdiff